The cycloidotron, a proposed crossed-field, fast wave millimeter tube

In general, the electrons of an electron beam in crossed electric and magnetic fields move in cycloids. The possibility of using such a beam in harmonic operation of a periodic-beam fast-wave tube has been explored. The most promising tube of tiffs type for a millimeter generator is one in which the ac motion occurs along the dc magnetic field and consequently is transverse to the dc motion. The small signal analysis of this tube is given, neglecting space charge, and it is shown that for reasonable beam currents backward wave oscillations at twice or even three times the cyclotron frequency can be obtained. The analysis is made particularly simple through the use of the small signal power theorem. Some of the practical problems associated with this tube are briefly considered.